A pressure gain combustor, an example of which is a pulse detonation engine (PDE), is a type of combustion engine that uses detonation waves to combust a fuel and oxidizer (e.g. air) mixture. Each detonation wave is initiated by an ignition source, and the combustion process is pulsated to allow the mixture to be renewed in a combustion chamber between detonation waves. Unlike a conventional pulse jet engine in which a fuel/air mixture undergoes subsonic deflagration combustion, a pulse detonation in a pressure gain combustor undergoes supersonic detonation. The combustion process greatly increases the combustion products pressure inside the combustion chamber, which then expands through a nozzle for thrust or power generation. This thrust can be used to propel a vehicle, or be converted into a mechanical power, e.g. by a rotary positive displacement device like a turbine coupled to a drive shaft.
In the past few decades, pressure gain combustors have been actively pursued as one of the most promising power generation cycles. Pressure gain combustors have the potential to provide significantly higher efficiency compared to the other power generation cycles. To realize this potential, operation of the combustion process must be optimized. Conventional control systems for combustion engines monitor the operation of the engine and control the fuel supply, air/fuel ratio, ignition timing and other functionality based on input variables. However, given the differences between a pressure gain combustor and conventional combustion engines, such as the transient operation and pulsating flow through a pressure gain combustor, conventional control systems for are not well suited for controlling the operation of a pressure gain combustor.